QLineEdit set min max range?

[jacek]

I try this:

You're on the right track.

It should be:

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}
 
	QValidator::State validate(QString & input, int &) const
	{
		// we don't have the access to private members of QDoubleValidator, 
		// so we must simulate them:
		const double b = bottom();
		const double t = top();
		const int d = decimals();
 
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		...
	}
};

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}

	QValidator::State validate(QString & input, int &) const
	{
		// we don't have the access to private members of QDoubleValidator, 
		// so we must simulate them:
		const double b = bottom();
		const double t = top();
		const int d = decimals();

		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		...
	}
};

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[whitefurrows]

Hi,

that's work fine. Thank you for your great help.

Greetings,

Whitefurrows

[whitefurrows]

Hi,

sorry i have trouble with my own QDoubleValidator, i set a Range 5-25 but i can't type 15 in to the QLineEdit:
myLineEdit->setValidator(new MyDoubleValidator( 5, 25, 2, myLineEdit));

Can anybody help me?

Greetings,

Whitefurrows

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent){}
 
	QValidator::State validate(QString & input, int &) const
	{
		const double b = bottom();
		const double t = top();
		const int d = decimals();
 
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;
 
		bool ok = false;
		double entered = input.toDouble(&ok);
		if (!ok) return Invalid;
 
		int nume = input.count('e', Qt::CaseInsensitive);
 
		int i; 
		if (input.contains(','))
			i = input.indexOf(',');
		else
			i = input.indexOf('.');
 
		if (i >= 0 && nume == 0) {
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Invalid;
		}
 
		if (entered < b || entered > t)
			return Invalid;
 
		return Acceptable;			
	}
};

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent){}
 
	QValidator::State validate(QString & input, int &) const
	{
		const double b = bottom();
		const double t = top();
		const int d = decimals();

		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;

		bool ok = false;
		double entered = input.toDouble(&ok);
		if (!ok) return Invalid;

		int nume = input.count('e', Qt::CaseInsensitive);

		int i; 
		if (input.contains(','))
			i = input.indexOf(',');
		else
			i = input.indexOf('.');
	
		if (i >= 0 && nume == 0) {
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Invalid;
		}

		if (entered < b || entered > t)
			return Invalid;

		return Acceptable;			
	}
};

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[jacek]

The problem is here:

if (entered < b || entered > t)
			return Invalid;

if (entered < b || entered > t)
			return Invalid;

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If the allowed range is 5--25, then "1" should be an intermediate value, not invalid one.
It should be probably:

if( entered < b ) {
   return Intermediate;
}
else if( entered > t ) {
   return Invalid;
}

if( entered < b ) {
   return Intermediate;
}
else if( entered > t ) {
   return Invalid;
}

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[whitefurrows]

Hi,

sorry i don't have get a notification. That's right, but the user can put wrong values to the QLineEdit.

What can i do?

Greetings,

Whitefurrows

[jacek]

That's right, but the user can put wrong values to the QLineEdit.

The problem is that line edit can loose focus when it contains an intermediate value. IMO you should ask the Trolls whether this is a correct behavior.

[whitefurrows]

Hi,

thank's to you. You know a way how can i set focus to a QLineEdit as long as contains an intermediate value?

Greetings

Whitefurrows

[jpn]

There are many ways to do that. You could override line edit's focusOutEvent(), use an event filter, or install an event filter even on the application. In all cases, you'll just have to ask the validator for it's state and then set the focus back on the line edit when appropriate.

[whitefurrows]

Hi,

can you help me to do that, please?

I try that:

protected:
	QLineEdit focusOutEvent(QFocusEvent* event) const;

protected:
	QLineEdit focusOutEvent(QFocusEvent* event) const;

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QLineEdit MyWidget::focusOutEvent(QFocusEvent* event) const{
	const QObject* ob=QObject::sender();
	int i =0;
	while (ob!=lineEditList[i] && i<lineEditList.size())
		i++;
 
	if(LineEdit Validator state == intermediate) //How can i do that?
                            leList[i]->setEditFocus(true);
}

QLineEdit MyWidget::focusOutEvent(QFocusEvent* event) const{
	const QObject* ob=QObject::sender();
	int i =0;
	while (ob!=lineEditList[i] && i<lineEditList.size())
		i++;

	if(LineEdit Validator state == intermediate) //How can i do that?
                            leList[i]->setEditFocus(true);
}

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Thanks in advance,

Whitefurrows

[jpn]

The focus out event could look for example something like this:

void MyLineEdit::focusOutEvent(QFocusEvent* event)
{
	// check validator state
	int pos = 0;
	QValidator::State state = validator()->validate(text(), pos);
 
	if (state == QValidator::Intermediate)
	{
		// keep focus if intermediate
		setFocus();
	}
	else
	{
		// otherwise call base class implementation and let it
		// handle focus out actions (so cursor stops blinking etc.)
		QLineEdit::focusOutEvent(event);
	}
}

void MyLineEdit::focusOutEvent(QFocusEvent* event)
{
	// check validator state
	int pos = 0;
	QValidator::State state = validator()->validate(text(), pos);

	if (state == QValidator::Intermediate)
	{
		// keep focus if intermediate
		setFocus();
	}
	else
	{
		// otherwise call base class implementation and let it
		// handle focus out actions (so cursor stops blinking etc.)
		QLineEdit::focusOutEvent(event);
	}
}

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If you have difficulties in subclassing QLineEdit, I suggest you to switch back to your favourite C++ book and learn the secrects of inheritance..

[whitefurrows]

Hi,

the problem is i can't subclassing QLineEdit. I use the designer and the designer use the QLineEdit and not MyLineEdit.

Sorry my stupid question i'm a beginner and learn. Please help me one more time.

Greetings,

Whitefurrows

[jpn]

You can use the subclassed line edit widget by promoting it as custom widget in the designer. See the context menu of the line edit.